High speed printing mechanism



J. LAST 2,988,987

June 20, 1961 HIGH SPEED PRINTING MECHANISM Filed March 1l, 1957 5Sheets-Shea?I 1 YANES LA ST WMA/ I Pam/ ATTO/ewa@ iJun-e 20, 1961 J.LAsT 2,988,987

HIGH SPEED PRINTING MECHANISM Fileed March 11 1957 v'5:7 Sheets-Sheet 21 Il /I ,y F 1,52. 13A

vr: i 30 "lflif; 29 I B2/1 d /zeA JAMES LAST /A/l/EA/,Toe

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June 20, 1961 J. LAST 2,988,987

HIGH SPEED PRINTING MECHANISM Filed March 1l, 1957 5 Sheets-Sheet 3ITAMES LHST /NVEN WMA/digli (a-JATToRA/f June 2o, 1961 J. LAST 2,988,987

HIGH SPEED PRINTING MECHANISM Filed March l1, 1957 5 Sheets-Sheet 4 ffa/I 3)/ June 20, 1961 J, LAST' 2,988,987

HIGH SPEED PRINTING MECHANISM Filed March l1, 1957 5 Sheets-Sheet 5JAMES LAST /Nl/E/VTO/Q n/mWi/M A TTORA/E YS United States Patent "O 2988987 HIGH SPEED riinsilNG James L'ast, St. Albans, England, assignor toElliott Brothers (London) Limited, London, England, a British Thisinvention relates to improvements in high speed printing mechanism. Thedevelopment of electronic computors has made important the provision ofprinting mechanism capable of operating at speeds such that advantagecan be taken of the very high speed of operation of such computors.

Accordingly, it is an. object of the invention to provide a mechanismcapable of printing during each operating cycle a character, selected bythe computor, in such a way that the operating cycle takes only a shorttime.

With'the foregoing object in view the present invention provides `a highspeed printing mechanism for the purpose referred to, which comprises acontinuously rotating type means, at least one hammer mounted formovement towards and away from the type means, means for acceleratingsaid hammer towards the type means and disengageable from said hammer atthe end of its driven stroke during which -said accelerating meansproceeds to its'position of rest which is out of the path of movement ofsaid hammer, means for imparting velocity to said accelerating member ata selected instant in the cycle of rotation of the type means and meansfor retaining s-aid accelerating member disengaged from the hammer oreach hammer when not required to accelerate the associated hammer.

Generally more than one character must be printed in a Kline and'accordingly a plurality of printing units would be assembled in `closelateral juxtaposition in order that, during each operating cycle, a lineof selected characters may be printed at a spacing of the same order asthat commonly given by a typewriter.

By way of example, the accompanying d-iagrammatic drawings illustrateembodiments of the invention. In the drawings:

FIGURE l is a side elevation view, partly in section, of one form ofprinting unit,

FIGURE 2 is a View similar to FIGURE 1 of another form of printing unit,

, FIGURES 2a, 2b and 2c are diagrammatic views showing components of theunit according to FIGURE 2 in various positions during an operatingcycle,

' FIGURE 3 is a view looking in the direction of arrow IIII in FIGURE 2,and

FIGURES 4, 4a, and 4b are fragmentary diagrammatic views of a modifiedform of printing unit, showing components at various positions during anoperating cycle.

The printing unit illustrated in FIGURE l comprises a continuouslyrotary type carrier consisting of an assembly of typewheels 1 eachhaving characters on its periphery, the type wheels being coaxiallymounted and keyed together on a common drive shaft 112.. Parallel to thetype carrier is a notched rotary cam 2 which is rotated con- -tinuouslyand synchronously in relation to the type carrier, so 'that a notch 3 ofsaid cam 2 passes a given point for every passage of a character past acorresponding point.

A. row of hammers 4, one for each typewheel, is provided, the head ofeach hammer being adapted to strike sheet material '5, such as a recordcard or web, placed between the hammers 4 and the type carrier. Hammeractuators 6 are provided which are retained, against the action ofsprings Z1, by selector latches 7, each acting on a step i8 on theassociated actuator 6.

V-shaped lugs 9, one on each actuator 6, are adapted to bear on thenotched rotary cam 2 to enter one of the cam notches 3 under the actionof 4actuator spring 21 when the step 8 of that actuator 6 which is to beoperated is released from its latch 7. 'Ihe action of the lever 6 isshown in greater detail in FIGS. 2a, 2b, 2c. FIG. 2a shows the lever inits unselected position. FIG. 2b shows the latch disengaged and the lug9 engaged with a cam notch 3. The nose 10 of the lever 6 is shown clearof the hammer tail 11 and the trunnion 20 displaced downwardly from thestep 20B, sliding for this purpose against the face 20C. FIG. 2C showsthe lever 6 raised mainly by rotation of the cam 2, to bring itstrunnion -again into contact with the step 20B and the lever nose 10behind the hammer ltail 11. Further rotation of the cam 2 expels the lug9 from the notch 3 of the cam 2 and swings the lever z6 about itstrunnion 20 to resume the position shown in FIG. 2a with the nose 1t)thereof underneath and clear of the hammer 4, which is displacedlengthways in its printing stroke during this movement.

Thus the mounting of this actuator '-6, and all other actuators, is suchthat its continued movement disengages the actuator nose 10 from thehammer end 11 just before the hammer head reaches the typewheel 1, thismovement leaving the hammer 4 free to rebound and also permitting theassociated selector latch 7 to re-engage the corresponding actuator step8.

Each latch 7 which serves to control a hammer actuator y6 issubstantially V-shaped and is rotatably mounted on a pivot pin 23. Thepivot pin 23 is positioned on a slotted mounting bar 24. Where, as willgenerally be the case, several latches 7 are used, they are operatedselectively, preferably, as shown, by electromagnetic means comprising'a plurality of electromagnets 13 each having an armature 14 providedwith a catch piece 15, engageable with a rocker 16 which co-operateswith the notched cam 2 and one of the selector latches 7. Each rocker116 is c-arried by a pivot pin 2S in a slotted mounting bar 26. A spring22 anchored between the rocker 16 and the associated latch 7 normallybiases the rocker 16 into engagement with the cam 2 and the latch 7towards its associated actuator 6.

The rotary cam 2 is common to all typewheels and thus bridges the spanof the typewheel assembly. The cam 2 and the typewheel shaft 12 are bothrotated by a train of toothed gears 27 from a suitable source ofrotatorymotion, such as an electric motor 2:8. Each typewheel 1 may haveassociated with it a hammer 4 and its actuator 6, and a selector latch7. Alternatively, the actuator, its selector latch and associated magnetmay be duplicated, two actuators operating on the same hammer. Thepaired groups of components are operable out of phase to double thefrequency of operation, the groups respectively con trolling alternateseries of characters.

lA resilient buffer 17 for limiting the stroke of the hammer toward thetype member is preferably provided as shown and this member 17 isadjustable in the direction of movement of the hammer 4 to suit variousthicknesses of material printed on.

Each hammer '4 is of parallel straight-Side form and extends radially ofthe typewheel 1, in a pair of guide notches 18A in a frame bar 18, thehammer 4 being slidably mounted to advance its head 4A toward andretract it from the typewheel 1 and being lightly biased by a spring 19to assist its rebound.

Each actuator 6 is in the form of a lever lying at an obtuse angle tothe axis along which the hammer slides and having its pawl-like nose 10adjacent to the tail end 11 of the hammer shank. This actuator lever hasa trunnion 20, formed at about the middle of its length, on which it canboth pivot and slide lengthwise. The spring 21 is connected at one endto the end of the actu- 3 i ator lever `6, remote from its pawl-likenose 10, and is anchored by its other end to frame bar 18 in such asense as to pull the actuator -lever 6 up towards the hammer 4 and alsoto swing the upper part thereof, betweenthe trunnion 20 and the hammer4, towards the rotary cam 2.

When the magnet catch piece l5 is withdrawn from the rocker 16 and thenose 16h drops into a notch 3 of the cam 2, the latch 7 is disengagedfrom the step 8 on the actuator `6 by the lower end of the rocker 16. Inthis arrangement the one cam 2 having notches 3 all around its peripheryis used to control both the actuator 6 and the rocker 16. The movementof the rocker 16 is due to the spring 22, the proportions of the members1'6 and 7 being such that ya bias in the required direction is provided.

FIGURES 2 and 3 of the drawings illustrate another construction of theprinting unit which differs slightly from that illustrated in FIGURE l.In this construction the substantially V-shaped selector latches 7 ofFIGURE 1 are replaced by substantially straight latches 7A each pivotedintermediately of its length on a pin 23A engaged in a slotted mountingbar 24A. The associated rocker 16A, supported by pin 25A in a slottedmounting block 26A is, in this arrangement, disposed below its latch 7Aand is rocked by engagement with the notches 29 of a separate rotary cam30 instead of by cam 2 as in the FIGURE l construction; cam 30 derivesits motion from gearing 27 driven by an electric motor as in FIGURE l.Because of the different disposition of the latches 7A and rockers 16Ait is more convenient to dispose the operating electromagnets 13A atright angles to the position shown in FIGURE l, so that the armatures14A thereof are `approximately vertical. The armature catch pieces 15Acoact with rockers 16A in substantially the same manner as in thearrangement of FIGURE l.

In some cases a pivoted hammer, instead of a sliding hammer, may beemployed.

FIGURE 4 illustrates an alternative form of hammer 4B and an actuator 6Afor use therewith. In this case the actuator 6A has a iixed pivot 20Aand on being released from its latch (not shown) the nose 10A thereofdisplaces the tail of the hammer 4B transversely of the length of saidhammer, which by reason of tension spring 19A, has a degree of springloaded transverse freedom in the necessary sense, in addition to thebias withdrawing said hammer from the type wheel 1, the spring loadingof the actuator 6A being adequate to cause such displacement of thehammer 4B. In FIG. 4a the lug 9A is shown entering a notch 3 and itsnose 10A just escaping from the tail of the hammer 4B, the hammer beingtilted against the downward component of the pull of the spring 19A, andin Fig. 4b the nose 10A is shown clear of the hammer tail and behind it,the lug 9A being in the notch 3 to full depth and the hammer 4B again inthe position shown in Fig. 4. On the expulsion of the `lug 9A from thenotch 3, due to rotation of the cam 2, the nose 10A swings to resume theposition shown in FIG. 4, displacing the hammer 4B lengthwise towardsthe typewheel 1 in doing so. The hammer rebound from the typewheel ishelped by the other, horizontal, component of the spring 19A.

In applying the above described mechanisms to the operation of lineprinting a number of units, each mechanism comprising a typewheel, ahammer, an actuator, a latch and an electromagnet, is assembled atcolumn pitch in a suitable frame as shown in FIGURE 3. In FIGURE 3 partsof some components are broken away for clearness. The common shaft l2 ofa common elongated typewheel is geared to the rotary cam 2 which extendsacross all column units. The cam conveniently has longitudinal grooves,the walls of which are at right angles constituting cam notches 3, thetrailing side of each groove being about twice as steep as the leadingside thereof.

In the construction shown in FIGURES 2 and 3 the type wheels each have50 characters and 10 blank places making 60 spaces in all. Also the cams2 and 30 each have fifty notches and a blank portion of the peripheryoccupying the space of 10 notches making 60 spaces in all. During thepassage of the 10 blank spaces past the printing line the paper may befed and the blank portions of the cams ensure that no hammers can beactuated during this period.

I claim:

l. A high speed printing unit for the purpose referred to, comprising aframe; a typewheel mounted thereon; means for continuously rotating saidtypewheel; a hammer slidable in said frame and having a head adjacent tothe typewheel, a shank arranged substantially radially thereto and atail remote therefrom; a spring acting to withdraw said hammer radiallyfrom the typewheel, a rigid lever of the second order rockable on saidframe and having a nose, a lug, a fulcrum and a tail, said lever havinga degree of endways freedom and making an obtuse angle with the shank ofthe hammer, a circular cam having notches in its circumference, meansfor continuously rotating said cam about an axis parallel to that of thetypewheel, a spring acting to swing the lever about its fulcrum in aplane normal to the axis of the typewheel to engage its lug with a notchin the cam and to bring its nose past the tail of the hammer, and alatch engageable with the tail of the lever, means for operating saidlatch at selected intervals of time to prevent such engagement butoperable to release the lever for engagement with the cam and the hammertail to effect the printing of a selected character presented by thetypewheel.

2. A high speed printing unit for the purpose referred to, comprising atypewheel; means for continuously rotating said typewheel; a hammersupport fixed adjacent said typewheel and having a downwardly facingsurface constituting a rst fulcrum abutment and beneath it andapproximately at right angles thereto another surface constituting asecond fulcrum abutment; a hammer having a head disposed opposite theperiphery of said typewheel, a shank carried by said support for slidingsubstantially radially to said typewheel and a tail remote from saidtypewheel; spring means acting between said support bar and said hammerto withdraw said hammer radially from said typewheel; a rigid actuatorcomprising a rockable lever of the second order having a nose forcooperating with said hammer tail, a fulcrum upon which said lever isrockable against said first fulcrum abutment on said support, a tailremote from said nose and a lug intermediately of said nose and saidfulcrum, said actuator lever making an obtuse angle with said hammershank, and having freedom for lengthwise displacement to move itsfulcrum between said rst and second fulcrum abutments; a circular camhaving notches in its peripheral surface and rotatable about an axisparallel to said typewheel; means for rotating said cam synchronouslywith said typewheel; a spring acting on said lever to swing it in aplane normal to the axis of said typewheel to engage its lug with anotch in said cam as said lever fulcrum moves between said fulcrumabutments and thus moves said lever nose into position behind saidhammer tail; a latch rockable upon a pivot parallel to said firstfulcrum abutment and acting on said lever tail normally to preventengagement of said lug with said cam notch but operable to release saidlever for engagement with said cam to propel said hammer tail to elfectendwise displacement of said hammer for cooperating with said typewheelfor performing a printing operation, and means for impartinglever-release movement to said latch at selected intervals of time.

3. A high speed printing unit for the purpose referred to, comprising atypewheel; means for continuously rotating said typewheel; a hammersupport fixed adjacent said typewheel; a hammer slidable in said supportand having a head disposed opposite the periphery of said typewheel, ashank supported substantially radially to said typewheel and a tailremote from said typewheel; a spring acting to withdraw said hammerradially from said typewheel; a rigid actuator comprising a rockablelever of the second order having a nose for cooperating with said hammertail, a fulcrum upon which said lever is rockable on said support, atail remote from the lever nose and a lug intermediately of said noseand said fulcrum, said actuator lever making an obtuse angle with saidhammer shank; a circular cam having notches in its peripheral surfaceand rotatable about an axis parallel to said typewheel; means forrotating said cam synchronously with said typewheel; a spring acting onsaid lever to swing it upon its fulcrum in a plane normal to the axis ofsaid typewheel to engage its lug with a notch in said cam and to moveits nose into position behind said hammer tail; a latch swingable upon apivot parallel to said lever fulcrum and acting on said lever tailnormally to prevent engagement of said lug with said cam notch; anelectromagnet having a movable armature; a rocker interposed betweensaid latch and said armature, means for imparting movement to saidrocker at selected intervals of time, coordinated movement of saidarmature towardsaid electromagnet when energised and of said rockerimparting swinging movement to said latch to release said lever forengagement with said cam, whereby said lever is impelled to strike saidhammer tail to impart a printing movement to said hammer.

4. A printing unit as claimed in claim 3, wherein said means forimparting periodic movement to said rocker is the said notched cam, asemployed to move the hammer actuating lever.

5. A printing unit as claimed in claim 3, wherein said means forimparting periodic movement to said rocker is a second notched camrotating synchronously with the cam which operates said hammer actuatinglever.

6. A high speed printing unit for the purposes referred to, comprising aframe; a typewheel journalled for rotation on said frame; typewheelrotating means; a hammer movably Supported on said frame in oppositionto said typewheel said hammer having a tail; spring means biasing saidhammer away from said typewheel; a hammeractuator lever rockable on theframe about a pivot intermediately of the length of the lever said leverhaving one end normally situated adjacent the tail of said hammer, aV-shaped lug projecting from the lever between said one end and saidpivot; a notched circular cam journalled in said frame for rotationabout an axis parallel to the pivotal axis of the lever having notchesadapted to be engaged by said lug; means for rotating said camsynchronously with said typewheel; second spring means biasing saidlever and said lug toward said notched cam and to dispose said one leverend behind said hammer tail; a latch rockable on said frame andcooperating with the other end of said lever to prevent movement of thelever by said second spring means, and means for rocking said latch atselected intervals of time to release said lever to engage said lug witha notch of said cam whereon rotation of the cam expels the lug from thenotch and swings the lever the said one end of which impels the hammertowards the typewheel.

References Cited in the le of this patent UNITED STATES PATENTS2,013,533 Buhler Sept. 3, 1935 2,030,427 Buhler Feb. 11, 1936 2,066,784Lake Jan. 5, 1937 2,227,143 Knutsen Dec. 31, 1940 2,566,944 Last Sept.4, 1951 2,766,686 Fomenlro Oct. 16, 1956 2,792,779 Toeppen May 21, 1957

